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COCONUT FIBER REINFORCED WALL PANELLING SYSTEM
MOHD HISBANY BIN MOHD HASHIM
UNIVERSITI TEKNOLOGI MALAYSIA
COCONUT FIBER REINFORCED WALL PANELLING SYSTEM
MOHD HISBANY BIN MOHD HASHIM
A project report submitted in partial fulfillment of the requirements for the award of the degree of
Master of Engineering (Civil-Structure)
Faculty of Civil Engineering Universiti Teknologi Malaysia
APRIL 2005
ii
iii
TO MY BELOVED PARENT,
HJ. MOHD HASHIM BIN ISMAIL
AND
HJH. CHE NAH BINTI HJ. MOHD YATIM
iv
ACKNOWLEDGEMENT
In preparing this project report, I wish to express my sincere appreciation to my main
supervisor, Professor Ir. Dr. Hj. Mohd Warid bin Hj. Hussin, for encouragement and
guidance in contributing towards my understanding and thoughts.
I would like to thank Mr. Leow Yuen Fooi from Boral Plasterboard (M) Sdn Bhd for
his contribution on the ideas and materials namely, gypsum plasterboard and coconut
fiber used in this investigation. My thank is also extended to the carpenters from Alor
Star, Encik Piji and Encik Azam that bring in the energy to help me in preparing the
samples. Also, the lab technicians at Heavy Structural Lab of Faculty of Civil
Enginering, Universiti Teknologi Mara, Pulau Pinang for their assistance in
highlighting on the uses and condition of equipment and facilities at the laboratory.
My fellow graduates students and colleagues should also be recognized for their
supports in their invaluable views.
I promise that I will never fail to remember how very grateful I am to all my family
members. My parents for their relentless prayer. My wife, Robiha Md Sabirin and
my three boys, Nazhif, Naufal and Nudzran for their patient and tolerant in allowing
me to complete this report.
v
ABSTRACT
A new material for wall boards in a composite of cement, gypsum and
coconut fiber as reinforcement is expected to be developed as replacement to brick
layering or to be used with the existing gypsum boards. Gypsum which is obtained
from crushing or calcining of natural gypsum, extracted from quarries has an
advantage of early hardening and fine finish, but it is limited to internal used due to
its sensitivity to water. Hardened Portland cement is strong and durable, but it does
not possessed early hardening or finishing characteristic for pre-cast components of
building material. The performance of eight flat board plates of 0.45 and 0.55
water/binder ratio with certain percentage of coconut fiber ranging from 2% to 4% of
weight of cement are tested for bending strength (flexural), compression strength,
density , moisture content and water absorption according to the procedure in BS
5669: Part 1 for particleboards. The sizes of specimen tested are 650 mm x 100 mm x
25 mm for bending, 160 mm x 40 mm x 40 mm for compression, and 100 mm x 100
mm x 40 mm for density, moisture content and water absorption. Specimens are
cured under water for maximum 28 days before testing at 3, 7 and 28 days. It is
found that addition and increase of coconut fiber do not contribute to bending
strength. Compressive strength increases with addition of coconut fiber, even tough
compressive strength decreases with increases in water content. Increasing water
content does increase the density. Densities increase with lower water content of
coconut fiber. The densities are less than normal concrete at 2400 kg/m3 and
comparable to other new wall materials between 600 kg/m3to 1800 kg/m3. There is
no significant change of moisture content with coconut fiber. Moisture content
increases with time. There is also no significant effect to water absorption on
increasing coconut fiber content. Hence, it indicates that the formulation can resist
the penetration of water better.
vi
ABSTRAK
Sejenis produk baru untuk kegunaan pembuatan dinding yang mengandungi
komposit bercampur simen, gypsum, dan sabut kelapa (gentian kelapa) sebagai
tetulang adalah diharapkan dapat dibangunkan sebagai pengganti kepada cara lama
penyusunan batu bata atau untuk digunakan dalam dinding pelapis gypsum sedia ada.
Gypsum didapati daripada proses penghancuran atau ‘calcining’ batuan gypsum asal
yang dikeluarkan daripada kuari mempunyai keistimewaan cepat mengeras dan
kehalusan rupa permukaan , tetapi ianya terbatas untuk kegunaan dalaman kerana
sentisif terhap air. Simen yang telah keras adalah kuat dan tahan lama, tetapi tidak
mempunyai sifat cepat mengeras atau rupa permukaan yang halus. Keupayaan lapan
jenis spesimen rata yang mempunyai nisbah air kepada bahan 0.45 dan 0.55 serta
dicampurkan beberapa peratus gentian kelapa berdasarkan berat simen yang
digunakan, telah diuji untuk kekuatan lenturan, kekuatan mampatan, ketumpatan,
kelembapan dan penyerapan air mengikut piawaan BS 5669: Bahagian 1. Ukuran
spesimen yang digunakan adalah 650 mm x 100 mm x 25 mm untuk lenturan, 160
mm x 40 mm x 40 mm untuk mampatan, 100 mm x 100 mm x 40 untuk ketumpatan,
kelembapan, penyerapan air. Spesimen diawetkan didalam air selama 28 hari dan
diuji untuk 3, 7, dan 28 hari. Adalah didapati menambah dan meningkatkan kuatiti
gentian kelapa tidak memperbaiki kekuatan lenturan. Kekuatan mampatan meningkat
dengan penambahan gentian kelapa walaupun kekuatan mampatan menurun dengan
kenaikan kuatiti air. Ketumpatan meningkat dengan peningkatan kuantiti air.
Ketumpatan didapati kurang daripada ketumpatan konkrit biasa iaitu pada 2400
kg/m3 dan sepadan dengan bahan baru yang lain diantara 600 kg/m3 dan 1800 kg/m3.
Kelembapan tidak banyak berubah dengan penambahan gentian kelapa. Kelembapan
juga tidak banyak berubah dengan peningkatan kuantiti gentian kelapa. Oleh itu,
formulasi baru ini didapati baik untuk mengawal kemasukan air.
vii
TABLE OF CONTENT
CHAPTER TITLE PAGE
Title Page i
Declaration ii
Dedication iii
Acknowledgement iv
Abstract v
Abstrak vi
Table of Content vii - ix
List of Tables x – xi
List of Figures xii – xv
List of Symbols xvi
1 INTRODUCTION
1.1 Background 1 - 2
1.2 Problem Statement 2 - 3
1.3 Objective and scope of study 3
1.4 Significant of Research 4
2 LITERATURE REVIEW
2.1 Introduction 5
2.2 Gypsum product 6
2.2.1 Composition of gypsum 6 - 7
2.2.2 Manufacturing of gypsum wallboards 7 - 8
2.2.3 Properties of gypsum 8 - 10
2.3 Natural Fiber reinforced partition wall 10
2.3.1 Coconut Fiber 10 -11
viii
2.3.2 Natural Fiber component 11 -12
2.3.3 Fiber processing 12
2.3.4 Properties of hardened Coconut fiber
reinforced wall 13
2.3.4.1 Compressive strength and durability 14
2.3.4.2 Tensile strength 14
2.3.4.3 Flexural strength 14
2.4 Manufacturing of fiber reinforced cement composite
2.4.1 Modified Hatschek Process for Cement Composite 15
2.4.2 Other methods 15
2.5 Conclusion 15
3 MATERIALS AND EXPERIMENTAL PROGRAMME
3.1 Introduction 25
3.2 Preliminary Investigation 26
3.2.1 Objective of Preliminary Mix Design 26
3.3 Raw Material 27 - 28
3.4 Trial Mix 28
3.5 Mixing Process 29
3.6 Casting, Curing and Testing 29 - 30
3.7 Experimental Programme 30 - 31
3.7.1 Material Sampling, Mixing, casting, and curing 31 - 32
3.8 Samples Identification 32 - 33
3.9 Type of test, size of test specimen, control,
and equipment
3.9.1 Bending Strength Test 33
3.9.2 Compression Strength 34
3.9.3 Density, Moisture Content and Absorption 34 - 35
3.9.4 Location of Test 35
3.10 Conclusion 35
ix
4 RESULTS AND DISCUSSION
4.1 Introduction 54
4.2 Bending Strength 54 - 55
4.2.1 Results for 3 day-test 55 - 56
4.2.2 Results for 7 day-test 56 - 57
4.2.3 Bending test result for 28 day-test , analysis,
discussion and conclusion 57 - 59
4.3 Compressive Strength 59 - 60
4.3.1 Compressive strength for 3 day-test 60 - 61
4.3.2 Compressive strength for 7 day-test 61
4.3.3 Compressive strength for 28 day-test, analysis,
discussion and conclusion 62 - 63
4.4 Density 63 - 64
4.4.1 Results for density, analysis, discussion and
conclusion 64 - 65
4.5 Moisture Content 66
4.5.1 Results for moisture content, analysis
and discussion 66 - 67
4.6 Water Absorption 68
4.6.1 Results for water absorption, analysis,
discussion and conclusion 68 - 69
4.7 Conclusion 69
5.0 CONCLUSION AND RECOMMENDATION
5.1 Conclusion 119 - 121
5.2 Recommendation for future works 121 - 123
REFERENCES 124 - 126
x
LIST OF TABLE
TABLE NO. TITLE PAGE 2.1 Chemical composition of coconut Fiber 16
2.2 Average properties of Coconut Fibers 16
3.1 Chemical Composition of Ordinary Portland Cement produced by CIMA 36
3.2 Chemical Composition of Gypsum Plasterboard Powder 36
3.3 Description of Test series B 37
3.4 Description of Test series C 37
4.1 3 Days Bending strength of a series of eight boards 70
4.2 3 days Average bending strength 71
4.3 7 Days Bending strength of a series of eight boards 72
4.4 7 days Average bending strength of eight series boards 73
4.5 28 Days Bending strength of a series of eight boards 74
4.6 3, 7 and 28 days Average bending strength of eight series boards 75
4.7 3 Days Compressive strength of a series of eight boards 76
4.8 3 days average compressive strength of eight series boards 77
4.9 7 Days Compressive strength of a series of eight boards 78
4.10 7 days average compressive strength of eight series boards 79
4.11 28 Days compressive strength of a series of eight boards 80
4.12 3, 7 and 28 days Average compressive strength of eight
series boards 81
xi
4.13 3 Days Density of a series of eight boards 82
4.14 7 Days Density of a series of eight boards 83
4.15 28 Days Density of a series of eight boards 84
4.16 The average density for eight series of boards 85
4.17 28 Days Moisture Content of a series of eight boards 86
4.18 7 Days Moisture Content of a series of eight boards 87
4.19 Average Moisture Content for eights series of boards 88
4.20 28 Days Water absorption of a series of eight boards 89
4.21 Average water absorption for eight series of specimen 90
xii
LIST OF FIGURES
FIGURE NO. TITLE PAGE 2.1 Schematic diagram of gypsum board manufacturing 17
2.2 Gypsum Plasterboard used in dry areas such as (a) wall and (b) ceiling 18
2.3 Gypsum Plasterboard used in wet areas such as bathroom 19
2.4 Wet/dry strength ratio of various Gypsum-Cement-Silica fume blends at different mix ratios, at constant water to cementitious material ratio of 0.5, after 3, 28, 200 days of water immersion 20
2.5 The effect of Portland cement content on the density of gypsum-portland cement blend. 20
2.6 The effect of gypsum content on density of gypsum-Portland cement-natural pozzolan blends 20
2.7 The effect of natural pozzolan content on density of Portland cement-natural pozzolan blends 21
2.8 The effect of superplastisizer on the water requirement of gypsum –portland cement -natural pozzolan blends with the composition of 41:41:18. 21
2.9 Cross section of a coconut palm 22
2.10 Cellular structure of vegetable fibers 22
2.11 Fiber preparation processes. 23
2.12 Modified Hatschek Process for manufacturing fiber reinforced cement sheet 24
2.13 Slurry infiltration process using steel fibers 24
3.1 Ordinary Portland Cement used 38
xiii
3.2 Gypsum casting plaster used 38
3.3 Samples of the coconut fiber used in the study 39
3.4 Product data sheet for admixtures used in the composite 40
3.5 Mixing was carried out by hand (manually) 41
3.6 Gypsum is being added to the mechanical mixer 41
3.7 (a) Original condition of the fibers upon arriving at laboratory (b) Coconut fibers that have been selected by pulling out 42
3.8 Treated coconut coir is left on open space for drying 43
3.9 Mechanical Vibrator used 43
3.10 80 gal square curing tank 44
3.11 (a) Samples of mould, (b) preparation and (c) equipment in preparing the molds 45
3.12 Diagram of the mould prepared for (a) bending (b) density, moisture, content and absorption (c) compression 46
3.13 Flexural test machine, ADR –Auto, ELE (100 kN) 47
3.14 A specimen ready to be tested for flexural test 47
3.15 Test specimen for compression strength 48
3.16 The cutting of samples into smaller size of test specimen 48
3.17 Compression Machine 2000kN, EL 49
3.18 Test specimen is being place on the compression testing machine 49
3.19 Size of test specimen for testing density, moisture and absorption 50
3.20 (a) Drying oven used in the testing for moisture content (b) samples placed in the oven 51
3.21 Flat bottom container used for testing absorption 52
3.22 Weighing the test specimen 52
3.23 Electronic caliper 53
xiv
4.1 Arrangement for measuring bending strength 91
4.2 Specimens are ready to be tested for bending strength 91
4.3 Bending strength for eight series of board at 3 days 92
4.4 Bending strength for eight series of board at 7 days 92
4.5 Bending strength for eight series of board at 28 days 93
4.6 Bending strength for eight series of board at 3,7 and 28 days test 93 4.7 Bending strength for eight series of board at 3,7 and 28 days test 94 4.8 Control samples (a) B: zero fiber, 0.45 water/binder ratio (b) control samples C: zero fiber , 0.55 water/binder ratio 95 4.9 Specimen B2, B3, and B4 ready cured and to be tested 95
4.10 Specimen C2, C3, and C4 after curing and ready for testing for bending 96 4.11 Crack or failure pattern of control specimen B and C after
bending test 97
4.12 Crack or failure pattern of control specimen B2, B3, and B4 98
4.13 Crack or failure pattern of control specimen C2, C3, and C4 99
4.14 Crack or failure pattern of control specimen C2, C3, and C4 100
4.15 Distribution of coconut fiber in the composite (section) (a) series B2 (b) series B3 (c) series B4 101 4.16 Distribution of coconut fiber in the composite (section) (a) series C2 (b) series C3 (c) series C4 102 4.17 Set up of the compressive stress parallel to the plane of the board 103 4.18 Average compressive strength for eight series of board
at 3 days 104
4.19 Average compressive strength for eight series of board at 7 days 104
xv
4.20 Average compressive strength for eight series of board at 28 days 104
4.21 Average compressive strength for eight series of board at 3,7 , 28 days 105 4.22 Compressive strength for eight series of board at 3, 7 and 28 days test 106 4.23 Appearance of control specimen (a) Series B without
fiber (b) series C without fiber 107
4.24 Appearance and failure pattern of specimen (a) B2 (b) B3, and (c) B4 108
4.25 Appearance of of specimen (a) C2 (b) C3, and (c) C4 109
4.26 Failure pattern of specimen (a) C2 (b) C3 and (c) C4 110
4.27 Average density for eight series of board at 3,7 and 28 days test 111
4.28 Average density for eight series of board at 3,7 and 28 days test 112
4.29 The physical appearance of control specimen for density and moisture content testing (a) control B (b) control C 113
4.30 Physical appearance of specimen with fiber B2, B3 and B4 used in density and after drying in oven moisture content 114
4.31 Physical appearance of specimen with fiber C2, C3 and C4 used in density and after drying in oven for moisture content 115
4.32 The graph of the average moisture content (in percentage) of a series of eight boards 116
4.33 Average of percentage of moisture content with regards to time 117
4.34 Average water absorption for eights series of boards 118
xvi
LIST OF SYMBOLS
P - flexural strength
W - load
Y - span (length)
B - width
T - thickness
Kp - compressive strength
A - area
Ρ - density
M - mass
V - volume
Wm - moisture content
Mh - mass
Mo - mass
O - Absorption
M1 - mass
M2 - mass
CHAPTER 1
INTRODUCTION 1.1 Background
Panelized wall paneling system is commonly used in industrialized countries
such as Singapore, Hong Kong, Taiwan, Korea and Japan. The used of these types
of pre-cast housing material is strongly promoted by their respective construction
authority.
The main reasons for the popularity of these dry wall systems are higher
productivity, site cleanliness, and improve wall finishes strength. Under the 8th
Malaysian Plan, the Malaysian Government has targeted 650,000 residential units
should be built by both the government and private sectors to meet the market
demand [1]. The targeted units will create a huge opportunities for the demand of
internal wall partition system for the bedroom, kitchen, bathroom and living rooms.
The majority of the existing internal wall partition system for residential
building is made of clay bricks and cement sand bricks which require 20 mm
plastering on both sides. There are readily available and cheap to construct with
recognized disadvantages of heavy loading, low productivity, high wastage and
requiring skill labor to install. Aerated concrete blocks are also being used. Even
though this material is found to be lightweight, good fire resistance, uniform
appearance, it is said to be generally brittle, weak and has high water absorption rate.
2
As such, the development of an alternative material such as natural fiber
reinforced paneling wall is expected to offer better improvement in term of the
weight (loading), speed in erection, superior finishes compare to the traditional
plastering of brick wall. The application of fiber reinforced cement in plasterboards
as wall partitioning has been widely accepted in the construction industries.
Basically there are two classification of fiber in the reinforcement of concrete
namely synthetic fibers and natural fibers. Usually the synthetic fibers come from
the family of polymer and some of the examples are glass fiber, polypropylene and
Kevlar. Natural fibers can be extracted from bamboo, sisal, jute, vegetable fibers and
etc [2]. Asbestos cement fiberboard is one examples of the used of fiber reinforced
material. Asbestos cement fiberboard has been used in Brazil extensively even
though the material is considered hazardous and damaging the environment.
A study conducted by Fadhadli [3] on the used of coconut fiber in cement
sheet for roofing demonstrated significant increment of flexural strength of flat plates
roofs. According to a survey conducted by the Agricultural Ministry of Malaysia [4]
there are about 156,000 hectares of coconut plantation in Peninsular Malaysia alone.
As such, there is a huge potential waste of these materials in this country that can be
utilized for construction industry especially in the production of new material.
1.2 Problem Statement
A large amount of agricultural waste was disposed in most of tropical
countries especially in Asia for countries like Thailand, Philippine and Malaysia. If
the waste cannot be disposed properly it will lead to social and environmental
problem.
Recycling of the disposed material is one method of treating the agricultural
waste. The used of coconut fiber from the dispose of coconut shell could be a
valuable material in the formation of a composite material that can be used as an
3
internal panel wall in housing construction. At present, there is a material made from
gypsum that is used as a partition wall either in dry or wet area. However, the used
of these gypsum boards involve a lot of steel bracing and bolt connections in the
installation works. Moreover, the space between the layers of the gypsum boards
will be void or fill up with wool in order to reduce noise and heat transfer or for
insulation purposes.
As such, a new material for plasterboards in a composite of cement, natural
fiber (coconut fiber) and gypsum is expected to be developed as replacement to brick
layering or to be used with the existing gypsum boards.
1.3 Objective and scope of study
The main purpose of the investigation is to determine the basic physical
behavior of the coconut fiber reinforced wall paneling system with cement and
gypsum binder with regards to physical properties, strength and durability.
The specific aims of the investigation are:
(i) To find the optimum mix design with regards to the amount of water,
fibers, cement, and gypsum ratio required.
(ii) To investigate the physical properties of the fiber reinforced boards –
density (lightweight), strength (bending and compression), water
absorption and moisture content
4
1.4 Significant of Research
(a) To show the improvement of the composite material in term of weight
(density) so the material provides faster and easy erection process.
(b) To increase the amount of information on physical or behavior of the
composite material.
CHAPTER 2
LITERATURE REVIEW 2.1 Introduction
The research activities for the last two decades has shown a considerable
effort towards the application of vegetable or plants fibers which exist in abundance
in the tropical and subtropical countries as reinforcing material for the production of
building components. The component comprises of the combination with cement
mortar or cement paste matrix. The revolution in the agricultural sector has resulted
in significant increases in the quantities of agricultural by product and wastes of
different types. The types of agro wastes that has been studied as reinforcement in
thin and plate sections in the production of wall or ceiling boards or particles boards
are coconut (shell and husks), jute, bagasse, sisal, wood, palm oil biomass to names a
few. The most common product of wall partitioning system is gypsum boards.
Gypsum and Portland cement are viable cementation material used widely for
the production of building materials. Gypsum is added to clinker in grinding at the
end of the manufacturing process of cement to control the hardening velocity of the
cement. Gypsum has an advantage of early hardening and fine finish, but it is
limited to internal used due to its sensitivity to water. Hardened Portland cement is
strong and durable, but it does not possessed early hardening or finishing
characteristic for pre-cast components of building material.
6
2.2 Gypsum product Gypsum is found in many parts of the world. Gypsum is one of the common
minerals in sedimentary environment. Gypsum deposits were formed millions of
years ago when salt water oceans covered most of the earth. As the deposit receded
and with the process of evaporation continued, they became more and more salty.
As those salts precipitated, they formed various compounds one of which was
gypsum. Through millions of years processed , these salt deposits combined with
decayed vegetation and other minerals, and eventually the result was stratified rock,
with layers of gypsum and layers of limestone alternating, the whole covered over
with many feet of glacial deposits.
The used of gypsum can be routed to many earlier years ago where the
ancient Assyrians called the beautiful rock Alabaster and it was used for sculpturing.
The Egyptians at five thousand years ago had learn to make plaster from gypsum
where they apply gypsum to line the wall of their palaces and their tombs. Its use by
the Greeks influences certainly in the name by which the rock is known. They called
it Gypsos, the source of the word "gypsum." The forerunner of wallboard,
plasterboard was invented in the United States in 1894 by one Augustine Sackett. A
highly ingenious system, it is based on the principle of a panel sandwich made up of
a gypsum core and sheets of cardboard stuck on each face.
2.2.1 Composition of gypsum
It is non-metallic mineral that composed of 79.1% calcium sulfate and 20%
water by weight. It is a major rock-forming mineral that produces massive beds
usually from the precipitation of highly saline waters. In chemistry term it is called
calcium sulfate dehydrate with chemical formula of CaSO4.2H2O. Pure gypsum, like
limestone, is white in color, however in the presence of impurities the gypsum rock
may appear gray, brown, pink or even almost black.
7
Gypsum is produced commercially from open pit quarries. The gypsum rock
would be grounded a white powder and it has to go through the process of
calcinations to remove its water content to produce calcium sulfate hemi hydrate
(CaSO4.1/2H2O) commonly called stucco in order to be produced for plaster or
wallboards. Heating gypsum above approximately above 150oC will partially
dehydrates the mineral, by driving off exactly 75% of the water content in its
chemical structure as shown in the chemical equation.
CaSO4.2H2O + heat CaSO4.1/2H2O + 1 ½H2O (steam).
The gypsum powdered can be molded into any desired shape after mixing
with water where it forms a pliable, plastic mass. After which it will harden and
retain that shape and recrystallize and technically has been restored to its original
rock-like state.
2.2.2 Manufacturing of gypsum wallboards The largest part of gypsum used goes into internal wallboard or drywall of
offices and homes. Wallboard is made from plaster obtained from the crushing and
calcining of natural gypsum extracted from quarries, or from chemical gypsum,
called desulfogypsum. In the manufacturing process of wallboard, stucco from
storage is first mixed with dry additives such as perlite, starch, fiberglass or
vermiculite. This dry mix is combined with water, soap foam, accelerators and
shredded paper in a mixer. The gypsum boards are formed by sandwiching a core of
wet plaster between two sheets of heavy paper that serve as a mold. The heavy paper
are continuously unwound, one unrolls under the mixer, and the other above it. The
top sheet of wallboard paper closes the mold which is thus formed, and the edges are
glued to the folded edges of the bottom sheet. The entire unit is laminated by a roller
or a forming plate and transported to the conveyor belt, then by rollers, up to the
shearing stage.
8
Once the plaster has set, the boards are cut to the proper length, turned over
so that the wallboard paper is not damaged in the following transfer steps, then
distributed among the various shelves in the dryer. Still wet at this stage, the
wallboard dries for approximately 45 minutes, then it is removed from the drying
oven. The sandwich will become strong, rigid, and fire proof building material called
gypsum or calcium sulfate dehydrate when the cores dry out. The wallboard is then
cut again to the specific length by rotary saws, assembled, then stacked in piles,
depending on the thicknesses and later use. The wallboard is now ready to be
distributed to the site.
Figure 2.1 shows the schematic diagram in the manufacturing of plasterboard.
A typical used of gypsum board is shown in Figure 2.2 for the dry areas and Figure
2.3 for a wet area.
2.2.3 Properties of hardened gypsum board
Mixing gypsum and Portland cement is usually unfeasible because it can
result in the formation of entringite or thaumasite depending on the amount of blend
of gypsum which will cause expansion and deterioration in concrete [5]. Entringite
is the result of blend with minor gypsum and thaumasite is the result of major
component of gypsum in the blend. A definition of ettringite is found in the
American Concrete Institute's "Cement and Concrete Terminology" (ACI 116R) in
which ettringite is described as a mineral, high-sulfate calcium sulfoaluminate
occurring in nature or formed by sulfate attack on mortar and concrete through
expanding crystalline growth within the voids (or cracks) in the concrete, creating
internal stresses that disrupt the concrete eventually cause loss of strength in concrete
[6].
Entringite and thaumasite occurs in the forms of spalling, expansion,
cracking, loss of strength and adhesion to the composite that contain gypsum.
Entringite formation in general associated primarily with expansion, cracking and
9
spalling, whilst, thaumasite formation further aggravate the hardened composite into
pulpy masses due to loss in strength [7].
It is known that gypsum with an addition of Portland cement and pozzolana
has potential for developing improved durability in water environment. Study
indicated that a blend of 75% gypsum plaster (calcium sulfate hemihydrate), 20%
Portland Cement and 5% Silica fume as pozzolana was recommended for obtaining
gypsum based material for improving resistance in humid environment [5].
Other material used as pozzolons that give similar results has been obtained
for the gypsum-Portland cement blend are fly ash [8], granulated blast furnace [9,10],
or natural pozzolan [11]. A study by Colak [12] recommended that gypsum -
portland cement - natural pozzolan blend of composition 41:41:18 and 41:41:18S1
(with 1% superplastizer) give an excellent retention properties after ageing in water
at 20oC for 95 days.
The most important result was that the wet strength and the wet/dry strength
ratio in the gypsum – cement – silica fume paste continue to increase compared to
pure gypsum alone because of dissolution of gypsum in water over time [13]. Figure
2.4 [13] shows the difference composition ratio with regards to wet/dry strength and
time of water immersion.
The results of the composition of 41:41:18 gypsum – Portland Cement –
natural pozzolan are shown in Figure 2.5, Figure 2.6 , Figure 2.7 and Figure 2.8 [12].
The finding shows that there is a general increase in the density as the content of
Portland Cement increases, the density of the blend decreases as the natural pozzolan
content increases, increasing of superplastisizer content decreases wet/binder ratio,
and increasing of gypsum content between 51% and 75% does not provide reduction
in density of the blend.
The test mentioned above showed that there is a general increase in density of
gypsum- Portland cement blend as the component of cement is increasing (Fig 2.5));
10
the increase of gypsum content leads to decrease in density and more or less stable in
the range of 50% - 75% (Fig 2.6); the density of blends decreases with rising natural
pozzolan content and becomes constant in the range of 20% -30% (Fig 2.7); and
increasing superplasticisers permit greater water reduction (Fig 2.8).
2.3 Natural Fiber reinforced partition wall Vegetables fibers are complex natural composite with a cellular structure The
last three decades has seen many efforts by researchers in studying the application of
natural fibers such as coconut fibers, bagasse, jute, flax, sisal, vegetable fibers, and
cellulose fibers as reinforcement in construction material [14]. Coconut fiber has
been studied in the production of thin plate concrete for replacing asbestos cement
product [3] and as mortar composite [14]. A study using other part of coconut fruit,
such the coconut shell has shown an encouraging result [15]. The research
demonstrated that an increase in cement content to grounded coconut shell increased
the bending strength and resistance to water absorption.
Great public concerned on the disposal of waste material may offer a solution
to high demand of construction material due to urbanization and fast population
growth that contribute to the growth of construction industry. As such, coconut fiber
has the potential to be used as reinforcement in internal wall paneling system with
binder component of cement and gypsum.
2.3.1 Coconut Fiber
Coconut cultivation can be found spreading across the tropical and
subtropical regions between the latitudes 20oN and 20oS. It can be seen in most of
Asia countries especially Thailand, Indonesia and India and Malaysia and the
tropical climate countries like Hawaii and Fiji Islands. Coconuts are mainly
cultivated on the coastal clays and sands. Coconut tress can grow up to 30 m height.
